ISOLATION AND SCREENING OF PROBIOTICS FROM TRADITIONAL FERMENTED FOODS FOR PREPARATION OF FUNCTIONAL BEVERAGES
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Date
2018-11
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UHF, NAUNI
Abstract
ABSTRACT
The present investigation was carried out to isolate most efficient potential probiotic microorganisms
from rare and unexplored food/beverages, their screening, identification, safety assessment, evaluation of
probiotic attributes and microencapsulation using sodium alginate matrice as well as development of functional
beverages. In total 77 bacterial isolates were obtained from fermented food/beverages. The morphological and
biochemical characteristics of all the isolates were studied. Among bacteria most of them were found to be gram
positive and catalase negative and were tentatively identified as Lactobacillus and Lactococci. All these 77
isolates were tested for their antagonistic activity against three test indicators viz. Listeria monocytogenes
MTCC 839, Bacillus cereus CRI and Staphylococcus aureus IGMC by bit/disc method and thirty bacterial
isolates were further selected for bacteriocin production. Among them, four isolates were finally selected on the
basis of their wide inhibitory spectrum against tested pathogens and on their bacteriocin producing potential
tested by well diffusion method. These isolates were identified as Lactobacillus fermentum Cha4, Enterococcus
lactis Dh2 Enterococcus durans TP2 and Enterococcus lactis TP2 by 16S r RNA gene technique. Safety
assessment of all four selected LAB was done by evaluating haemolytic, DNase and gelatinase activities and
showed negative results, thereby proving their safe status. All the isolates exhibited 90-100% antibiotic
sensitivity. These screened isolates were further examined for their probiotic potential viz. acidity tolerance, bile
tolerance, autoaggregation, co-aggregation, hydrophobicity, BSH activity, β-galactosidase production, sodium
nitrite depletion antioxidant activity, siderophore production and cumulative probiotic potential. All the four
screened isolates found to be highly acidity tolerant strains with 98.88-775.3 % survival rate at pH 3 for 180
min. These four isolates were able to resist high bile salt concentration i.e. 2.0% with 93.69-77.53% survival
rate for 8 h. All the four isolates exhibited good autoaggregation capacity i.e. greater than 40% after 5 h and
showed strong hydrophobicity towards xylene i.e. > 40%. All the four isolates showed good antioxidant
activity, depletion of sodium nitrite and cholesterol reduction Microencapsulation of screened probiotic isolates
was done using different matrices. All these four screened isolates were qualified with high cumulative score of
100%, thus showed their strong probiotic potential. Out of total four isolates Lactobaciilus fermentum Cha4 had
been used to prepare probiotic enriched functional jamun RTS. Hence, this study affirms the potential use of
probiotic microorganisms in the development of new therapeutic functional foods and nutraceutical preparations
to impart goodness to health.
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